Precision Machined from 6061-T6 Aluminum and finished in a Matte Black Hard Coat Anodization. Features 15 M-LOK Slots Across 3 Slot Tracks for Mounting Accessories with an Additional 4 Slots at the Front Along the 45 Degree Tracks. 24 Slot Full-length Top Picatinny Rail Flush and Continuous with Upper Receiver. Ergonomic Octagonal Profile with Thoroughly Machined Lightening Cuts. Integral Anti-rotation Tabs Accurately Aligns Upper Receiver and Prevents Handguard Rotation and Flex. Patented Steel Barrel Nut Requires no Timing of the Gas Tube or its Installation Screws. Compatible with Left or Right Handed Mil-spec Upper Receivers. Compatible with Standard Mil-spec. Forged AR15 Upper Receivers, Compatibility with Billet Upper Receivers is Not Guaranteed, Barrel Nut Fits Over Barrel Diameters up to 1.05. Actual Length from Flush with Receiver to Furthest End of Handguard, 9.75